Question 55114
The slope, m, is defined as {{{m=(y[2]-y[1])/(x[2]-x[1])}}}.  It doesn't matter which ordered pair is {{{x[1]}}},{{{y[1]}}} and {{{x[2]}}},{{{y[2]}}} because you'll get the same answer.  Using substitution we get {{{m=(-5-8)/(5-6)}}}, which simplifies to {{{m=-13/-1}}}, which reduces to {{{m=13}}}.